Transformades de Fourier aplicades a marcatge invisible d’imatges digitals

Abstract

[en] In this work it has been designed a steganographic method for embedding watermarks in invisible digital images based on the Fourier transform and resistant to the printing and scanning process. The objective of this method is to facilitate the tracking of possible leakage points or filtration of private documents. The water- mark is embedded over the magnitude coefficients of the Fourier transform. The measure Peak signal-to-noise ratio is used to evaluate the degradation of the image quality after marking. A detection rate is defined to check the resistance of the watermark to different geometric attacks and, finally, to the printing and scanning process.